Heater Connections

[Copper01]

On the 427sc with an FE, does it matter which heater hose goes to which connector on the heater box? Also, which hose gets the flow control valve or does it matter? Any photos would be most helpful.

With respect to the air box under the dash, does anyone have any diagrams as to which air lines hook up where and where the box itself mounts? Again, any photos would be most appreciated.

We finally finished getting moved into our new house and I've only got a couple of weeks left in EMT school, so I'm most hopeful that I'm going to be able to dedicate some time to my Cobra.

Ben Bruce
Unique 427
SA 427SO w/ Toploader
Guardsman Blue

[eliminator]

Ben,

I have pictures of both areas, and yes it does matter. Send me your e-mail address.

Eliminator

[davids2toys]

I know this is an old thread, but it is one of the ones that came up with a search on "HEATER". I also have question concerning the heater hose setup being correct. I have a 1993 car and my heater/blower motor looks to be a little different that the pics I am seeing using the search function. I did not build this car and I am thinking this thing is setup wrong. The core has been marked IN and OUT by the original owner, but as I said, seems wrong. Just like the original starter of this thread, I have the same question, does it matter which one is the "IN" or the "OUT"?
He put the cable style flow control in the return hose to the water pump which is going to the heater core nipple that says "IN". He put the vacuum flow control valve in the hose going to the intake manifold and this hose is connected to the heater core nipple marked "OUT"
Is there a need for two different types of flow control valves? I would think you would just need one going into the "IN" side of the heater core. I also think that hose is the one coming from the intake manifold?
I will post a pic, hopefully this helps.
Please pardon my mess as I am refreshing the engine bay a little bit.
Thanks...Dave

[davids2toys]

Does anybody know exactly what the vac switch in the hose, and the firewall solenoid are supposed to do? I thought it actually opened the valve when it sees vacuum once the solenoid is activated by turning on the blower motor on. I am now thinking vacuum would not be enough to power a water valve to open. Is it maybe an inline valve/ temp sensor that sends a signal to the soleniod on the firwall, and along with engine vac tells the blower motor it is OK to come on?
Is there any direction or work instructions for this system?

[davids2toys]

Did some testing, vacuum actuated valve in the heater line does work correctly..the electric solenoid appears not to be working correctly. When the blower motor is off it shows no current to either leg, when the blower motor is turn on, it shows current at both legs, but it does not open to let vacuum go thru other hose to the inline valve. Should it be showing current to both legs? I'm thinking no, but I am no expert in electrical theory. I'm thinking maybe it is shorting out?
I still think this inline heater hose valve should be in the line coming off the manifold.
Any thoughts?
Thanks...Dave

[Jim Harding]

Should it be showing current to both legs? I'm thinking no, but I am no expert in electrical theory. I'm thinking maybe it is shorting out?
Any thoughts?
Thanks...Dave

Dave, first let's get on the same page.........

There are two things some people get confused about, they are voltage and current. You can have voltage and NO current, but you can't have current without voltage. You measure voltage by placing you meter probes ACROSS the device to be checked, and you measure current by removing one wire from the device and placing your meter probes: one on the wire removed and the other on the device the wire was attached to, or in other words, in SERIES with the device.

To check your solenoid, follow these steps:

The convenient way to measure voltage (to see if a device is in it's ON or OFF state) is by connecting the black or negative (minus) probe of the voltmeter to the frame of the vehicle, which is normally connected to the negative post of the battery. You then check for voltage at BOTH of the terminals of the solenoid.

With a solenoid that SHOULD be in it's ON state, measuring the SAME voltage on both contacts of the solenoid indicates the solenoid is most likely OK but there is no ground connection to the solenoid. (i.e. no current flowing) In many cases, devices are turned on or off by placing a switch in the ground lead of the device.

Measuring voltage at ONE terminal (the positive one) and none at the other usually means the devise your checking is defective (if you're expecting an ON state). Measuring no voltage at either terminal indicates a normal OFF state, and if your expecting an ON condition, check the fuse and/or wiring for defects.

In order to confirm this condition, disconnect ONE lead from the solenoid and re-measure the voltage at both terminals. If you removed the wire that should be grounded, the voltages at the solenoid will be the same as measured above. If the voltage is zero at the solenoid, then you removed the positive or 12 volt source.

Now that you have identified the positive and negative terminals of the solenoid, connect a jumper from the NEGATIVE lead of the solenoid and touch the other end of the jumper to ground (frame of vehicle) A good, working solenoid should turn on. A bad one will do nothing.

Let me know what you found.

Jim

[davids2toys]

Hi Jim,
I just answered your PM, Thanks again for the theory lesson.
OK, here goes.
First paragraph: When measuring voltage across the terminal I got nothing, when checking current, I also got nothing.
Third paragraph: with the blower on I got 11.5 on both legs. If I use a test light, the terminal connected to the positive wire was brighter.
sixth paragraph: I remove the non positive wire and the voltage was the same on both legs. I also took the test light and hooked it up to a positive terminal and put the probe to the wire and got no light, so I think that is one of my problems.
Seventh paragraph: solenoid did nothing. The way I have been testing the solenoid is connecting a vac pump to the one side of the solenoid, pump it up to 20, and a vacuum gauge end of the line at the heater hose vacuum valve. Turn the blower motor on, and nothing, vacuum holds on one end and remains zero at the gauge.
So i am thinking I need a new solenoid and trace that wire to where it is supposed to be grounded. Under my dash is so crowed I cant see a thing.
Is this the one, looks the same to me.
http://ambulanceparts.com/electricva...dsolenoid.aspx
or
http://www.fixmyambulance.com/produc...%2052-0161.htm

As far as the connections are concerned, does it matter which side of the heater core is the "in" and which is the "out"?

Is there a need for this solenoid and the vac operated water control valve? Could I just use the manual operated valve in the hose going to the inlet side of the core. Why the original owner/ builder put a water control valve in the hoses to both sides of the heater core, I have no idea...am I missing something here?
Thanks...Dave

[davids2toys]

double post

[Jim Harding]

Hi Jim,
I just answered your PM, Thanks again for the theory lesson.
OK, here goes.
First paragraph: When measuring voltage across the terminal I got nothing, when checking current, I also got nothing.
Third paragraph: with the blower on I got 11.5 on both legs. If I use a test light, the terminal connected to the positive wire was brighter.
sixth paragraph: I remove the non positive wire and the voltage was the same on both legs. I also took the test light and hooked it up to a positive terminal and put the probe to the wire and got no light, so I think that is one of my problems.
Seventh paragraph: solenoid did nothing. The way I have been testing the solenoid is connecting a vac pump to the one side of the solenoid, pump it up to 20, and a vacuum gauge end of the line at the heater hose vacuum valve. Turn the blower motor on, and nothing, vacuum holds on one end and remains zero at the gauge.
So i am thinking I need a new solenoid and trace that wire to where it is supposed to be grounded. Under my dash is so crowed I cant see a thing.
Is this the one, looks the same to me.
http://ambulanceparts.com/electricva...dsolenoid.aspx
or
http://www.fixmyambulance.com/produc...%2052-0161.htm

As far as the connections are concerned, does it matter which side of the heater core is the "in" and which is the "out"?

Is there a need for this solenoid and the vac operated water control valve? Could I just use the manual operated valve in the hose going to the inlet side of the core. Why the original owner/ builder put a water control valve in the hoses to both sides of the heater core, I have no idea...am I missing something here?
Thanks...Dave

OK Dave, let me draw a conclusion from your tests.......

Third paragraph: with the blower on I got 11.5 on both legs. If I use a test light, the terminal connected to the positive wire was brighter.

OK, this a good sign that the solenoid "might" be OK. Here's what happened in your test; The test light was brighter on the positive because the light was "seeing" the 11.5 volts you measured. It was dimmer when probing the negative terminal because the internal resistance of the solenoid was causing a voltage drop at that terminal. Lower voltage = dimmer light.

sixth paragraph: I remove the non positive wire and the voltage was the same on both legs. I also took the test light and hooked it up to a positive terminal and put the probe to the wire and got no light, so I think that is one of my problems.

You are correct. There is an "open" circuit on that negative (non-positive) wire. It has to be "seeing" ground (negative post of the battery).

Seventh paragraph: solenoid did nothing. The way I have been testing the solenoid is connecting a vac pump to the one side of the solenoid, pump it up to 20, and a vacuum gauge end of the line at the heater hose vacuum valve. Turn the blower motor on, and nothing, vacuum holds on one end and remains zero at the gauge.

OK, try reversing the wires on the solenoid. And I'm assuming that during this test, you grounded the negative wire on the solenoid, correct? My thinking is that it shouldn't make a difference, but try it anyhow.

So i am thinking I need a new solenoid and trace that wire to where it is supposed to be grounded. Under my dash is so crowed I cant see a thing.

It's a heck of a coincidence that you would have an open circuit on the negative wire AND a bad solenoid, but if your tests were run as you described, then I'd have to agree with you.

As far as the other questions concerning how that thing operates, I can't comment because I have no experience how they are designed to work.

Is there a need for this solenoid and the vac operated water control valve? Could I just use the manual operated valve in the hose going to the inlet side of the core. Why the original owner/ builder put a water control valve in the hoses to both sides of the heater core, I have no idea...am I missing something here?

There is the KISS method "Keep It Simple Stupid"! I don't know why that wouldn't work.

[davids2toys]

OK Dave, let me draw a conclusion from your tests.......

Third paragraph: with the blower on I got 11.5 on both legs. If I use a test light, the terminal connected to the positive wire was brighter.

OK, this a good sign that the solenoid "might" be OK. Here's what happened in your test; The test light was brighter on the positive because the light was "seeing" the 11.5 volts you measured. It was dimmer when probing the negative terminal because the internal resistance of the solenoid was causing a voltage drop at that terminal. Lower voltage = dimmer light.

sixth paragraph: I remove the non positive wire and the voltage was the same on both legs. I also took the test light and hooked it up to a positive terminal and put the probe to the wire and got no light, so I think that is one of my problems.

You are correct. There is an "open" circuit on that negative (non-positive) wire. It has to be "seeing" ground (negative post of the battery).

Seventh paragraph: solenoid did nothing. The way I have been testing the solenoid is connecting a vac pump to the one side of the solenoid, pump it up to 20, and a vacuum gauge end of the line at the heater hose vacuum valve. Turn the blower motor on, and nothing, vacuum holds on one end and remains zero at the gauge.

OK, try reversing the wires on the solenoid. And I'm assuming that during this test, you grounded the negative wire on the solenoid, correct? My thinking is that it shouldn't make a difference, but try it anyhow.

So i am thinking I need a new solenoid and trace that wire to where it is supposed to be grounded. Under my dash is so crowed I cant see a thing.

It's a heck of a coincidence that you would have an open circuit on the negative wire AND a bad solenoid, but if your tests were run as you described, then I'd have to agree with you.

As far as the other questions concerning how that thing operates, I can't comment because I have no experience how they are designed to work.

Is there a need for this solenoid and the vac operated water control valve? Could I just use the manual operated valve in the hose going to the inlet side of the core. Why the original owner/ builder put a water control valve in the hoses to both sides of the heater core, I have no idea...am I missing something here?

There is the KISS method "Keep It Simple Stupid"! I don't know why that wouldn't work.

So why when I tested voltage the way you were tell me in para 3 did it test exactly the same with the voltmeter? I did do the jumper thing in the present wire configuration, but I did not do it when reversing the wires which was before I started working with you on this. OK, I just went out there and did it with wires reversed using a jumper to ground. Still not working.
Thanks for all your help and hopefully somebody else chimes in as far as the proper hook up of this heater core and all the hoses and valves involved
Thanks again Jim...Dave

[Jim Harding]

So why when I tested voltage the way you were tell me in para 3 did it test exactly the same with the voltmeter?

I think you are referring to reading the same voltage on both terminals of the solenoid, but seeing different brilliance with your test light.

In this case, with the negative terminal NOT grounded, there is no current flow in the circuit, and both terminals of the solenoid will indicate the same (source) voltage. When measuring with your voltmeter (on the negative terminal), there WILL be a VERY small current flow through the solenoid due to the meters very high internal resistance, but almost unmeasurable voltage drop across the solenoid. When using your test lamp, it requires a higher current to light the bulb, and WILL cause a voltage drop across the solenoid. To see this in action, connect your test light from the negative terminal to ground. Then, using your voltmeter, measure the voltage across the test light and the solenoid. Add those two voltages together, and it will equal source voltage.

In science it's called "Kirchhoff's Voltage Law"

Hope you can get this all ironed out before winter!!!

[davids2toys]

Holy Crap Jim,
I am following you about 50% on this one. I guess you really are pretty good with this stuff, I'll take your word on it...LOL
I will try what you said next time I get back out there
Thanks